An ansa-metallocene is an organic metal compound containing two ligands that are linked by a bridge group. The bridge group prevents rotation of the ligands and determines the structure and activity of the metal center.
One potential application of ansa-metallocenes is in polymerization reactions for olefin homopolymers or copolymers. Particularly, ansa-metallocenes based on cyclopentadienyl-fluorenyl ligands have become of great significance in the polymerization of high-molecular weight polyethylenes with controlled microstructures. In addition, ansa-metallocenes containing indenyl ligands have excellent activity and can be used to produce polyolefins with high stereoregularity.
As such, although various studies on ansa-metallocene compounds that have higher activity and yet can control the microstructure of olefin polymers are underway, the results are unsatisfactory.